The present invention relates to a high-speed intermittent rotary mechanism. More particularly, this invention relates to a mechanism which consists of a set of parallel shafts having two pairs of gears respectively mounted thereupon, wherein one pair or both pairs are cam gears. The driven shaft is rotatable by means of bearings, while two driving gears are fixed on the driving shaft at an axial location corresponding respectively to the corresponding meshing gears and the respective gear pairs have equal center-to-center distances. An epicyclic train of gears is also provided. A set of gears of the epicyclic train of gears are planet gears and are driven by one driven gear meshed with one driving gear. A ring gear of the epicyclic train is driven by means of the other driven gear meshed with the other driving gear thus causing the planet gear and the ring gear to revolve around a sun gear mounted on the driven shaft. A difference in speed between the ring gear and the planet gears will occur because of the change in the revolving radii of a pair of cam gears, and an intermittent rotary motion with periodic dwell-and-movement of the driven shaft is thus obtained.
In the conventional intermittent rotary mechanisms, a movement with a predetermined length is produced by a repeatedly periodical dwell-and-movement through the motive force of a driving shaft rotating at a constant speed. There are many kinds of such mechanisms with comprehensive applications. Usually, assemblies of intermittent gearing or of ratchet feeding mechanisms are used. In addition ratchets of the steel ball or the roller type, or coil spring ratchets and/or friction ratchet are also used. The main point concerning an intermittent rotary mechanism using an interrupted-tooth gear assembly or a ratchet feeding mechanism lies in that after the intermittent movement and during the stationary or dwell period, the driven gear cannot make any small rotation, thus requiring a device to confine motion. If not, while in the beginning of intermittent motion, the meshing of the interrupted-tooth gear will cause the gears in normal position to shift erroneously so that no satisfactory transmission can be obtained. In order to eliminate this defect, a convex surface is provided at a portion of the driving body of the gear assembly mentioned above. In addition, a concave surface is provided at the driven body opposite and corresponding to the convex surface, rendering the driving body, during idling, pressed tight between the concave surface and the convex surface, and effecting a sliding motion on the other side, to prevent errors between the meshed teeth of corresponding convex and concave shapes in the beginning of transmission. As to the ratchet wheel assembly, a click is generally provided for the prevention of reverse rotation and also to serve as a means for adjusting any abnormal rotations. This kind of intermittent movement device will generally give birth to a sudden and sharp impact action during start and stop. Therefore, it is impossible to obtain an accurate intermittent movement and such a device is inapplicable in high-speed operation for a driven body that requires a large transmitting power.
The primary objective of the present invention is to improve the defects mentioned above, and to provide an intermittent rotary mechanism in which several rotational bodies are pivotally connected by means of bearings. The assembly of a revolving wheel train of planet gears rotatable by means of pairs of cam gears is completely constituted of transmission gears, without any wearing parts and local frictions, thus eliminating completely the sudden and sharp impact action during the start and the stop of a general intermittent movement applicable in transmitting heavy items and for large motive forces at high speed and sensitivity with practically no noises.
Other objects, advantages and operating principles of the intermittent rotary mechanism according to the present invention will be understood from the following detailed description when read in light of the accompanying drawings.